Calculator for guitar chords

Abstract

An electronic device in the nature of a hand-held calculator, for illustrating on the display area required string and fret positions of a fretted stringed instrument to be fingered to play the notes making up a particular chord. The device comprises a series of manually operable basic chord information buttons and a visual representation of the strings of the fretted instrument and of the frets over a particular range is also provided. A ROM means is programmed with chord table information relating chords in desired keys with related fret and string finger position information. A microprocessor means is electronically associated with the chord information switches, open string position indicator LED's, first fret reference LED's, fret and string finger position LED's stores information concerning the particular chord information buttons and upon being actuated, the microprocessor searches the ROM means for fret and finger position information corresponding to the chord information button or buttons actuated, and displays that information by way of illuminating means in the appropriate areas of the fret and string representation. Such a device adopts logic technology to store and reproduce in a display area information as selected concerning the strings and fret positions to be fingered for any selected predetermined chord on a fretted stringed instrument through the application of an appropriate logic system.

Description

BACKGROUND OF THE INVENTION

This invention relates to an electronic device, in the nature of a hand held calculator, for displaying in sequence intervals of chords for various keys for a fretted stringed instrument. More particularly, the invention relates to an electronic device which uses a logic system for storing, and then displaying as selected, the finger positions for the strings of a fretted stringed instrument represented by a selected chord or selected series of musical intervals in a selected key. Variations of the device permit sequential displaying of alternative finger positions for a particular chord, sequential display of different types of chords (e.g. major, minor, diminished, augmented, etc.) once a particular key has been selected, and sequential display of a particular type of chord in different keys.

Of background interest is my co-pending U.S. application Ser. No. 871,173 filed Jan. 23rd, 1978 for "Electronic Display Device for Fretted Stringed Instruments". That application relates to an electro-mechanical system for displaying in a display area the finger positions for the strings of a fretted stringed instrument represented by a selected key and a selected series of musical intervals. What appears in the string and fret display is predetermined by the co-selection of related key and musical interval switches and does not require the use of any logic system other than in an associated numeric display used to identify the bar position fret for a selected chord. That device does not provide for chords having "open" strings, i.e. chords in which not all of the strings of the instrument are played, and is limited in the number of chords which can be displayed, since essentially a separate circuitry must be provided for each desired chord in each desired key.

Other references of background interest describing and illustrating display devices for stringed musical instruments having some electronic features include Johnson, Jr., et al U.S. Pat. No. 3,978,757 issued Sept. 7th, 1976, Weitzner U.S. Pat. No. 3,403,591 issued Oct. 1st, 1968 and Weitzner U.S. Pat. No. 3,379,087 issued Apr. 23rd, 1968.

SUMMARY OF THE INVENTION

In accordance with the present invention, an electronic device in the nature of a hand held calculator is provided for illustrating on the display area required string and fret positions of a fretted stringed instrument to be fingered to play the notes making up a particular chord. The device comprises a series of manually operable basic chord information buttons. Each button is associated with a corresponding chord information switch with one chord information switch for each chord or musical interval for which finger position information is desired. A visual representation of the strings of the fretted instrument and of the frets over a particular range is also provided. Electronically actuated fret and string finger position indicator means are associated with the fret and string representation, each of the string finger positions for each of the frets having electronically actuable indicator means associated with it. Electronically actuated open string position indicator means are associated with each string of the fret and string representation to indicate when a corresponding string is not fingered. An electronically actuated first fret reference indicator means to represent a fret reference point for a selected chord is provided. A ROM means is programmed with chord table information relating chords in desired keys with related fret and string finger position information. Microprocessor means is electronically associated with the chord information switches, open string position indicator means, first fret reference indicator means and fret and string finger position indicator means. The microprocessor is adapted to store information concerning the particular chord information switch or switches actuated until there is actuation of a manually operable select means associated with a select switch means. The microprocessor then searches the ROM for fret and finger position information corresponding to the chord information switch or switches actuated, and displays that information on the appropriate fret and string finger position indicator means, open string position means and first fret reference indicator means. A manually operable switch means is electronically associated with the microprocessor and fret and string finger position indicator means to clear information displayed on the fret and string representation as required. The device according to this invention provides an accurate visible indication on the fret and string representation, of the string and fret positions to be fingered for any selected predetermined chord. Such a device adopts logic technology to store and produce in a display area information as selected concerning chords in any key or a fretted stringed instrument through the application of an appropriate logic system.

In one embodiment of this invention, each basic chord information button and corresponding chord information switch represents a particular key in the chromatic scale and is independently and not simultaneously actuable with respect to other chord information switches and corresponding chord information switches. A series of chord indicator buttons and corresponding chord indicator switches are provided representing types of chords, with the chord indicator switches being electronically associated with the microprocessor and each not being simultaneously actuable with each other but simultaneously actuable with the chord information switches. The microprocessor is also adapted to store information regarding the particular chord indicator switch actuated until the select switch means is actuated. The microprocessor then searches the ROM for fret and finger position information corresponding to the chord information and chord indicator switches which are actuated, and displays that information on the appropriate fret and string finger position indicator means, open string position indicator means and first fret reference indicator means.

In another embodiment according to the present invention, each basic chord information button and associated switch represents a different musical interval. Each such basic chord information button and switch is simultaneously actuable with other such buttons and switches. A selection button and associated switch is provided so that, after actuation of the desired basic chord information switches, actuation of the selection switch causes the function of predetermined basic chord information buttons and switches to be converted to that of representing the keys in the chromatic scale. Each such switch, functioning in this key representing capacity, is not simultaneously actuable with other such similarly functioning switches. These chord information switches functioning as key selection switches simultaneously act as select switch means.

A series of chord alternative position indicator buttons and corresponding chord alternative position indicator switches may be further provided to the device of the present invention to show alternative chord positions for a particular chord on the fret and string finger position indicator means and fret and string representation. The chord alternative position switches are electronically associated with the microprocessor and are each simultaneously actuable with the chord information switches, but independently and not simultaneously actuable with other chord alternative position indicator switches. The ROM means is programmed with chord table information relating to alternative chord positions for chords and keys with related alternative fret and string finger position information. The microprocessor is also adapted to store information concerning the particular chord alternative position indicator switch which is actuated, until such time as the select switch is actuated, and then search the ROM for fret and string finger position information corresponding to the particular chord information switch and chord alternative position indicator switch actuated. That information is then displayed on the appropriate fret and string position indicator means, open string position indicator means and first fret reference indicator means.

The device according to the present invention permits storage and reproduction on the visual representation of the device of a considerable volume of chording information (e.g. 1500 to 2000 different chords) for a guitar or similar stringed instrument. The device can be used by students or professional musicians alike for purposes of learning the appearance and location of chords on a stringed intrument and for a fast, easy identification of desired chords when composing or playing music.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon referring to the drawings in which:

FIGS. 1 to 5 are plan views of the faces of example embodiments of electronic devices according to the present invention;

FIG. 6 is a schematic block diagram of the logic and display features of the electronic device according to the present invention;

FIG. 7 is a circuit diagram of a portion of the circuitry of the embodiment of FIG. 1 according to the present invention;

FIGS. 8a, 8b, 8c and 8d, arranged as illustrated at FIG. 8e, show a circuit diagram of the example embodiment of FIG. 2;

FIGS. 9a, 9b and 9c show a flow diagram of the operation of the logic system of the embodiment of FIG. 1 according to the present invention; and

FIGS. 10a, 10b and 10c show a flow diagram of the operation of the logic system of the embodiment of FIG. 2 according to the present invention.

Similar features have been given similar reference numerals in the drawings.

While the invention will be described in connection with example embodiments, it will be understood that it is not intended to limit the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Turning first to FIGS. 1 to 5, there are shown example embodiments of electronic devices 2 according to the present invention. Each device has a frame 4 on which are mounted a series of manually operated basic chord information buttons 6, each such button being associated with a corresponding chord information switch 8 (FIG. 7 or 8a), one such chord information button and chord information switch being provided for each key in respect of which finger position information is desired (FIGS. 1, 3, 4 and 5) or for each musical interval in respect of which such finger position information is desired (FIG. 2). A visual representation 10 of the frets and six strings of the fretted stringed instrument over a range of four frets, is provided. It is preferably transparent except for lines thereon representing frets and strings of the instrument. Towards the top of the device 2 as can be seen in FIGS. 1, 2 and 8c and 8d, electronically actuated fret and string finger position indicator means 12, being LEDs, are associated with the fret and string visual representation, each of the string finger positions for each of the frets having one such LED associated with it. Above fret and string visual representation 10 are situated a row of fret indicator LEDs 14, the function of which is to indicate on which frets a particular chord displayed on visual representation 10, of the frets along the neck of the stringed instrument that chord is to be played. In the embodiments illustrated, this is done by taking as a reference point the left hand fret of visual representation 10, and identifying that fret on the neck of the stringed instrument by the number of the fret indicator LED actuated for that particular illustrated chord.

Also in FIGS. 1 to 5 to the left of visual fret and string representation 10 appears a row of open string indicator LEDs 16, each situated beside a corresponding representation of a string in string and fret representation 10. Illumination of one or more of such LEDs indicate that the corresponding string or strings are to remain open (i.e. played but without fingering) for that particular displayed chord.

Above visual fret and string representation 10 also appears an on/off indicator LED 18, the LED to be illuminated when the device is on and operational.

A manually operated select button 20 is provided on the face of the devices, and associated with select switch 22 (FIGS. 7 and 8a), the function and operation of which will be detailed subsequently herein.

The clear button 24 and associated switch 26 (FIGS. 7 and 8a) provided, the function of which button and switch is to erase undesired intervals or chords which have been called up by operation of chord information buttons 6 and switches 8.

Turning to the block diagram of FIG. 6, it can be seen that device 2 is provided with a microprocessor 28, which is fed information from keyboard 30, which keyboard includes chord information buttons 6, select button 20 and clear button 24. A read only memory means 32 (ROM) is also provided within the device, programmed with chord table information relating chords in desired keys with related fret and string finger position information. The microprocessor means is electronically associated with the chord information switches 8, fret indicator LED 14, open string position indicator LEDs 16 and fret and string finger position LEDs 12 and is adapted to store information regarding the particular chord information switch or switches actuated and, as required, then search the ROM for fret and finger position information corresponding to the chord information switch or switches actuated. That information is then displayed through illumination of the appropriate fret and string position indicator LEDs 12, fret indicator LEDs 14, and open string position indicator LEDs 16 in fret board display area 34. In this manner an accurate, visible indication is given in the fret board display area 34 of the strings and fret positions to be fingered for any selected predetermined chord.

Considering the differences between the embodiments illustrated in FIGS. 1 to 5, FIG. 1 illustrates a chord displaying device in which the chord information buttons 6 function strictly as the buttons which represent particular keys of the chromatic scale, these buttons being independently and not simultaneously actuable. A further series of buttons 38, being chord indicator buttons, and associated switches 40 (FIG. 7) are provided, the function of which buttons and switches is to relate a chord type (e.g. minor, major, diminished, dominant, augmented or suspended) to the selected key, such that when select button 20 is actuated, the fret and finger position information corresponding to the selected key and chord type is displayed in the fret and string representation 10. It will be understood that chord indicator switches 40 are each independently and not simultaneously actuable with other chord indicator switches.

Interval buttons 42, representing 6, 7 and 9 intervals, as well as associated switches 44 (FIG. 7) are also provided to further increase the chord characterization and identification possible with this device. Again the interval switches 44 are independently and not simultaneously actuable with each other, although each is simultaneously actuable with chord indicator switches 40 and chord information switches 8. Thus, if the location of a major 7 chord in the key of E is sought, the appropriate chord information button 6 (for the key of E), chord indicator button 38 (showing "M") and interval button 42 (showing the numeral 7) would be selected and, as will be described in more detail subsequently, actuation of select button 20 then results in the appropriate chord location being displayed in fret and string representation 10 and by fret indicator means 14 and open string indicator LEDs 16.

Finally, in FIG. 1, alternative positions of a selected chord (P¹, P², P³ and P⁴) are displayable using chord alternative position indicator buttons 46, each associated with a chord alternative indicator switch 48 (FIG. 7). Chord alternative indicator switches 48 are each independently and not simultaneously actuable with other such switches 48.

The device of FIG. 2 is intended to be used by both musicians or non-musicians to gain a fundamental or basic knowledge of chord structure. While similar in overall appearance to the embodiment of FIG. 1, the device illustrated in FIG. 2 is provided with chord information buttons 6 and associated switches 8 (FIG. 8a) functioning as musical interval selector switches so that the operator may select the desired interval required to form a particular chord. The function of the buttons and corresponding switches of the first two rows and the first two buttons of the third row is altered, however, upon actuating select button 20. These buttons and corresponding switches then function as chord selector switches. In operation, the microprocessor 28 obtains from ROM 32 the combined information concerning the particular musical intervals selected and the particular key selected to cause illumination of the proper fret and finger position LEDs 12 for visual fret and string representation 10 for that particular chord. It will be understood that the chord information switches 8, when functioning as interval number selector switches, are simultaneously actuable with other chord information selector switches, but when functioning as chord selectors are not simultaneously actuable with similar switches. Alternative indicator buttons 46, and associated chord alternative indicator swtiches 48 (FIG. 8a) function as previously described in respect of the device of FIG. 1.

From the foregoing, the function of the buttons of the keyboards 30 of the devices of FIGS. 3 and 4 will be readily understood. In these embodiments, additional key buttons and associated switches are provided such that the buttons and switches do not share functions, as in the case of the device of FIG. 2. For instance, in FIG. 3, if a D major 7 chord is required, the "D/D", "MAJ", and "7" buttons are actuated, and upon actuation of the "S" selection button 20, an appropriate finger positioning to play that chord is illustrated in visual fret and string representation 10 by fret and finger position LEDs 12, fret indicator LEDs 14 and open string indicator LEDs 16. The unit of FIG. 4 is similar to that of FIG. 3 except that it is provided with an additional chord alternative indicator button 47 (and associated switch), to provide optional display of five basic alternative positions for a particular selected chord. As well, in the upper row of keyboard 30 thereof, buttons 49 and associated switches are provided to give additional versatility to the unit. This row of buttons, with associated switches and related circuitry modifications which will be readily understood by one skilled in the art, permits chords displayed to also be placed in a memory location (by actuating button "ENT"). That chord may be called back automatically ("AUT" button) or manually ("MAN" button). When the "AUT" button is pressed, such stored chords will reappear on the display at a time set by a rotary wheel, not shown in dictating seconds when first placed into memory. When the "MAN" button is pressed, the memory is activated by way of adaptors and an auxiliary switch means, so that the stored chord is called back and displayed. The "CLM" button and associated switch functions to clear the memory of such a chord.

The device of FIG. 5 has a keyboard 30 set up generally similar to that of the unit of FIG. 1. Additionally however a tape recorder and playback means 50 is electronically associated with the unit to permit recording of characteristic signals received from the microprocessor relating to a sequence of selected chords, in such a manner that these signals may be subsequently played back to the microprocessor to cause to be illustrated on visual fret and string representation 10 an identical sequence of chord finger positions.

GENERAL DESCRIPTION OF CIRCUIT DIAGRAM

Referring to FIGS. 8a, 8b, 8c and 8d, it will be seen that this circuit diagram shows the entire circuitry and logic system that transforms signals entered through keyboard 30 into accurate visual LED representations at fret and string display 10, of chords thereby selected.

The circuit diagram of these Figures is representative of the circuitry and logic system of the unit illustrated in FIG. 2.

U1, U2 and U3 shown in FIG. 8a represent octal buffers with tri-state outputs to isolate switches from the data bus. These may be, for example Motorola 74LS241. Microprocessor 28 (for example Motorola 6802) is represented by U4 (FIG. 8b). 5a, 5b, 5c and 5d, and 6a, 6b and 6c represent nand gates (for example Motorola 74LS00 and 74LS10) (FIG. 8b), and U7 and U8 represent a 1 of 8 decoder (e.g. Motorola 74LS138) and a hex inverter (for example Motorola 74LS04) for address decoding and enabling of periphal I.C.'s. U9 and U10 represent 1,024×8 bit ROMs for program storage and data tables. These may be, for example Motorola 2708's, U11, 12, 13, 14 and 15 represent octal latches (for example Motorola 74LS373) for latching data to be displayed by fret and string finger position LEDs 12. U16 is a 1 of 16 decoder (for example Motorola 74LS154) for fret indicator LEDs 14.

In operation, on power up condition, the reset vectors are looked up from the ROM 32 at FFFE and FFFF and the reset routine is started. This clears all RAM in the microprocessor 28 and initializes the registers.

At this point, microprocessor 28 enables each of the three octal buffers (at addresses ∅F∅5, ∅F∅6, ∅F∅7) in turn (U1, 2, 3) and determines if any of the chord information buttons or keys are being pressed. The signals from these keys are stored in RAM locations (∅∅∅5 and ∅∅∅6) until such time as the select button 20 is pressed. When the select button has been pressed, microprocessor 28 takes the chord combination from RAM, and compares it with the valid chord table in ROM 32. When the valid chord is located, it is assigned a number which is stored in another RAM location (∅∅∅8).

At this time, a musical key and position are selected and this information is then also stored in RAM locations (∅∅∅A and ∅∅∅7 respectively). When all three variables are determined and valid, microprocessor 28 uses this information to look up in ROM 32 the "fret" number and display it using address ∅F∅∅ and then the "finger positions" on fretboard at addresses ∅F∅1-∅F∅4 inclusive. This information is stored in latches (U11, 12, 13, 14, 15) for continuous display.

Once data has been stored in the latches, the keyboard is continually scanned so that the "musical key" and fingering position can be changed for the selected chord.

When the "CL" button 24 is pressed, microprocessor 28 is forced into a reset condition and the whole process will start again and enable the user to define a new chord.

The flow diagrams of FIGS. 9a, 9b and 9c detail more specifically the stages of operation and of the logic system illustrated by the block diagram of FIG. 6 and circuitry of FIGS. 8a, 8b, 8c and 8d, for the device illustrated in FIG. 2.

Virtually identical circuitry is provided, for example, for the device of FIG. 1. The only modification to that circuitry is illustrated in FIG. 7 where it can be seen that chord information switches 8 serve only one function, i.e. to provide a direct chord access to the memory bank. The chord information switches 8 have only a single function and not, as in the device of FIG. 2, alternative functions. The operation of the circuitry and logic system of the device of FIG. 1 is very similar to that of the device of FIG. 2, with the exception that operation of the select switch 22, in the former, results in the retrieval of the necessary chord information from the ROM and display thereof on the appropriate LEDs in the fretboard display area 34, while the operation of select switch 22 in the case of the device of FIG. 2 simply changes the function of chord information switches 8 from interval selector to chord type selector.

A flow diagram of the logic system of the device of FIG. 1 is illustrated in FIGS. 10a, 10b and 10c.

Summaries of the latch functions for the devices of FIGS. 1 and 2 are set out in the following table. It will be clear to one skilled in the art, from this information, the manner in which the logic and circuitry of the devices of FIGS. 3, 4 and 5 may be set up.

Schedule A is a machine language program of the operation of the device of FIGS. 1 and 7, while Schedule B is a machine language program of the operation of the device of FIGS. 2 and 8a, 8b, 8c and 8d.

Thus it is apparent that there has been provided in accordance with the invention an electronic device in the nature of a hand held calculator that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.

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Schedule `A`
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∅∅∅∅     Temporary LED Storage for flashing
∅∅∅1       Key Press Duration group 1
∅∅∅2       Key Press Duration group 2
∅∅∅3       Key Press Duration group 3
∅∅∅4       "P/S" flag (is chord complete?)
∅∅∅5       Temporary chord Storage register
∅∅∅6       Not used
∅∅∅7       ROM Address for finger positions on frets
∅∅∅8       ROM Address for finger positions on frets
∅∅∅9       "P" flag (has position been selected?)
∅∅∅A       Temporary "KEY" Storage
∅∅∅B       ROM Address for fret selection
∅∅∅C       ROM Address for fret selection
∅F∅∅       Fret Position Latch
∅F∅1         Latches for finger positions
∅F∅2         Latches for finger positions
∅F∅3         Latches for finger positions
∅F∅4         Latches for finger positions
∅F∅5         T/S buffers for switches
∅F∅6         T/S buffers for switches
∅F∅7         T/S buffers for switches
∅3A∅-∅3BF
Valid chord look-up table
∅3C∅-∅3FF
Fret position ROM table
FC∅∅-FFFD
Finger position ROM table
FFFE-FFFF   Reset Vector
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Schedule `A`
Valid Chord Look up Table
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∅3A∅      ∅1
∅3A1        81
∅3A2        41
∅3A3        21
∅3A4        A1
∅3A5        ∅2
∅3A6        82
∅3A7        42
∅3A8        22
∅3A9        4∅
∅3AA        48
∅3AB        2∅
∅3AC        28
∅3AD        44
∅3AE        ∅8
∅3AF        5∅
∅3B1        XX
∅3B2        XX
∅3B3        XX
∅3B4        XX
∅3B5        XX
∅3B6        XX
∅3B7        XX
∅3B8        XX
∅3B9        XX
∅3BA        XX
∅3BB        XX
∅3BC        XX
∅3BD        XX
∅3BE        XX
∅3BF        XX
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Schedule `A`
Reset Routine
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LDA A      #$∅3
STA A      $∅B
LED Flash INC        $∅∅∅∅
LDA A      $∅∅
STA A      $∅F∅∅
Key Press LDA A      $∅F∅5
TST A
BNE        Key Group 1
LDA A      $∅F∅6
TST A
BNE        Key Group 2
LDA A      $∅F∅7
TST A
BNE        Key Group 3
CLR        $∅∅∅1
CLR        $∅∅∅2
CLR        $∅∅∅3
TST        $∅∅∅4
BNE        Key Press   P/S Flag
JMP        LED Flash
Key Group 1
CLR        $∅∅∅2
CLR        $∅∅∅3
INC        $∅∅∅1
LDA B      #$32
CMP B      $∅1
BNE        Key Press
TST        $∅∅∅4
BNE        Key Press
ORA A      $∅5
STA A      $∅5
JMP        LED Flash
Key Group 2
CLR        $∅∅∅1
CLR        $∅∅∅3
INC        $∅∅ ∅2
LDA B      #$32
CMP B      $∅2
BNE        Key Press
TST        $∅∅∅4 P/S Flag
BNE        "KEY" Key 1
LSR A
BCS        Chord Valid?
ROL A
JMP        "KEY" Key 1
Key Group 3
CLR        $∅∅∅1
CLR        $∅∅∅2
INC        $∅∅∅3
LDA B      #$32
CMP B      $∅3
BNE        Key Press
LDA B      #$FC
STA B      $∅∅∅7
LDA B      #$∅3
Pos Search
LSR A
BCS        Display
INC        $∅∅∅7
DEC B
BEQ        Display
JMP        Pos Search
Chord Valid
CLR A
LDX        #$∅3A∅
LDA B, X   $∅∅
CMP B      $∅5
BEQ        Valid
INX
INX
ADD A      #$∅4
CMP A      #$54
BEQ        Reset       (invalid chord)
JMP        Test
Valid     STA A      $∅8
LDA A      #$∅1
STA A      $∅4       Set P/S Flag
JMP        Display + 1
"KEY"  Key 1
CLR        $∅∅∅A
LDX        #$∅∅∅3
TAB
ASL B
Key Search 1
INC        $∅∅∅A
ASL B
BCS        "KEY" Key 2
DEX
BNE        Key Search 1
JMP        Key Press
"KEY" Key 2
ASL        $∅∅∅A
ASL        $∅∅∅A
LDX        #$∅∅∅4
DEC        $∅∅∅A
Key Search 2
INC        $∅∅∅A
ASR A
BCS        Display + ∅1
DEX
BNE        Key Search 2
JMP        Key Press
Display   LDA A      $∅1
STA A      $∅9       Set `P` Flag
Display + 1
TST        $∅∅∅9
BEQ        Key Press
TST        $∅∅∅4
BEQ        Key Press
LDA A      #$∅F
AND A      $∅7
ASL A
ASL A
ASL A
ASL A
ORA A      $∅A
STA A      $∅C
LDX        $∅B
LDA A, X   ∅∅
STA A      $∅F∅∅
LDX        $∅7
LDA A, X   ∅∅
STA A      $∅F∅1
LDA A, X   ∅1
STA A      $∅F∅2
LDA A, X   ∅2
STA A      $∅F∅3
LDA A, X   ∅3
STA A      $∅F∅4
JMP        Key Press
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Schedule `A`
Fret Position ROM Table
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Position 1
∅3C4     ∅∅   C
∅3C5     ∅1     C#
∅3C6     ∅2     D
∅3C7     ∅3     D#
∅3C8     ∅4     E
∅3C9     ∅5     F
∅3CA     ∅6     F#
∅3CB     ∅7     G
∅3CC     ∅8     G#
∅3CD     ∅9     A
∅3CE     ∅A     A#
∅3CF     ∅B     B
Position 2
∅3D4     ∅3     C
∅3D5     ∅4     C#
∅3D6     ∅5     D
∅3D7     ∅6     D#
∅3D8     ∅7     E
∅3D9     ∅8     F
∅3DA     ∅9     F#
∅3DB     ∅A     G
∅3DC     ∅B     G#
∅3DD     ∅∅   A
∅3DE     ∅1     A#
∅3DF     ∅2     B
Position 3
∅3E4     ∅8     C
∅3E5     ∅9     C#
∅ 3E6    ∅A     D
∅3E7     ∅B     D#
∅3E8     ∅∅   E
∅3E9     ∅1     F
∅3EA     ∅2     F#
∅3EB     ∅3     G
∅3EC     ∅4     G#
∅3ED     ∅5     A
∅3EE     ∅6     A#
∅3EF     ∅7     B
Position 4
∅3F4     ∅A     C
∅3F5     ∅B     C#
∅3F6     ∅∅   D
∅3F7     ∅1     D#
∅3F8     ∅2     E
∅3F9     ∅3     F
∅3FA     ∅4     F#
∅3FB     ∅5     G
∅3FC     ∅6     G#
∅3FD     ∅7     A
∅3FE     ∅8     A#
∅3FF     ∅9     B
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SCHEDULE `A`
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Finger Position ROM Table
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Position 1
FC∅∅  7D      FC8∅   BE    Major
FC∅1    DF      FC81     EF
FC∅2    BE      FC82     DF
FC∅3    EF      FC83     77
FC∅4    ED      FC84     F6    Major 6th
FC∅5    F7      FC85     FB
FC∅6    BF      FC86     DF
FC∅7    FF      FC87     FF
FC∅8    7B      FC88     BD    Major 7th
FC∅9    DF      FC89     EF
FC∅A    BE      FC8A     DF
FC∅B    F7      FC8B     7B
FC∅C    7B      FC8C     BD    Major 9th
FC∅D    DE      FC8D     EF
FC∅E    FE      FC8E     7F
FC∅F    FF      FC8F     7F
FC1∅    7F      FC9∅   BF    Major 6-9
FC11      77      FC91     BB
FC12      BF      FC92     DF
FC13      F7      FC93     FB
FC14      B5      FC94     B5    Minor
FC15      A5      FC95     A5
FC16      4B      FC96     4B
FC17      5B      FC97     5B
FC18      EF      FC98     F7    Minor 6th
FC19      F6      FC99     FB
FC1A      F7      FC9A     7B
FC1B      F7      FC9B     FB
FC1C      ED      FC9C     F6    Minor 7th
FC1D      FB      FC9D     FD
FC1E      BF      FC9E     DF
FC1F      FF      FC9F     FF
FC2∅    EF      FCA∅   F7    Minor 9th
FC21      7B      FCA1     BD
FC22      7F      FCA2     BF
FC23      FF      FCA3     FF
FC24      7D      FCA4     BE    7th
FC25      FB      FCA5     FD
FC26      BE      FCA6     DF
FC27      F7      FCA7     7B
FC28      FD      FCA8     FE    Augmented 7th
FC29      EF      FCA9     F7
FC2A      BB      FCAA     DD
FC2B      BF      FCAB     DF
FC2C      EF      FCAC     F7    9th
FC2D      7B      FCAD     BD
FC2E      BF      FCAE     DF
FC2F      BF      FCAF     DF
FC3∅    7D      FCB∅   BE    Augmented 9th
FC31      EE      FCB1     F7
FC32      FB      FCB2     7D
FC33      BF      FCB3     DF
FC34      DD      FCB4     EE    Diminished 7th
FC35      F7      FCB5     FB
FC36      7F      FCB6     BF
FC37      FF      FCB7     FF
FC38      7D      FCB8     BE    Augmented -FC39 EF FCB9 F7
FC3A      BE      FCBA     DF
FC3B      FF      FCBB     7F
FC3C      ED      FCBC     F6    Suspended 7th
FC3D      FB      FCBD     FD
FC3E      DF      FCBE     EF
FC3F      FF      FCBF     FF
Position 2
FD∅∅  7E      FD8∅   BF    Major
FD∅1    F7      FD81     7B
FD∅2    BF      FD82     DF
FD∅3    FF      FD83     FF
FD∅4    DE      FD84     EF    Major 6th
FD∅5    F7      FD85     7B
FD∅6    BF      FD86     DF
FD∅7    FF      FD87     FF
FD∅8    7E      FD88     BF    Major 7th
FD∅9    EF      FD89     77
FD∅A    F7      FD8A     FB
FD∅B    FF      FD8B     FF
FD∅C    7E      FD8C     BF    Major 9th
FD∅D    EF      FD8D     77
FD∅E    FD      FD8E     FE
FD∅F    BF      FD8F     DF
FD1∅    B5      FD9∅   B5    Major 6-9
FD11      A5      FD91     A5
FD12      4B      FD92     4B
FD13      5B      FD93     5B
FD14      7D      FD94     BE    Minor
FD15      F7      FD95     FB
FD16      BF      FD96     DF
FD17      FF      FD97     FF
FD18      DD      FD98     EE    Minor 6th
FD19      F7      FD99     FB
FD1A      BF      FD9A     DF
FD1B      FF      FD9B     FF
FD1C      ED      FD9C     F6    Minor 7th
FD1D      DF      FD9D     EF
FD1E      B7      FD9E     DB
FD1F      BF      FD9F     DF
FD2∅    FB      FDA∅   FD    Minor 9th
FD21      DF      FDA1     EF
FD22      BE      FDA2     DF
FD23      FF      FDA3     7F
FD24      FE      FDA4     FF    7th
FD25      DF      FDA5     6F
FD26      B7      FDA6     DB
FD27      FF      FDA7     FF
FD28      BE      FDA8     DF    Augmented 7th
FD29      DF      FDA9     6F
FD2A      D7      FDAA     EB
FD2B      FF      FDAB     FF
FD2C      FB      FDAC     FD    9th
FD2D      DF      FDAD     EF
FD2E      B7      FDAE     DB
FD2F      BF      FDAF     DF
FD3∅    EE      FDB∅   F7    Augmented 9th
FD31      F7      FDB1     7B
FD32      DD      FDB2     EE
FD33      FF      FDB3     FF
FD34      FD      FDB4     FE    Diminished 7th
FD35      F7      FDB5     FB
FD36      7F      FDB6     BF
FD37      EF      FDB7     F7
FD38      BE      FDB8     DF    Augmented
FD39      F7      FDB9     7B
FD3A      FF      FDBA     FF
FD3B      FF      FDBB     FF
FD3C      FF      FDBC     FF    Suspended 7th
FD3D      77      FDBD     BB
FD3E      BF      FDBE     DF
FD3F      F7      FDBF     FB
Position 3
FE∅∅  7B      FE8∅   BD    Major
FE∅1    EF      FE81     F7
FE∅2    BD      FE82     DE
FE∅3    FF      FE83     FF
FE∅4    7E      FE84     BF    Major 6th
FE∅5    EF      FE85     77
FE∅6    BD      FE86     DE
FE∅7    BF      FE87     DF
FE∅8    7B      FE88     BD    Major 7th
FE∅9    EF      FE89     F7
FE∅A    7F      FE8A     BF
FE∅B    FF      FE8B     FF
FE∅C    DB      FE8C     ED    Major 9th
FE∅D    EF      FE8D     F7
FE∅E    7F      FE8E     BF
FE∅F    FF      FE8F     FF
FE1∅    DE      FE9∅   EF    Major 6-9
FE11      EF      FE91     77
FE12      FD      FE92     FE
FE13      BF      FE93     DF
FE14      7B      FE94     BD    Minor
FE15      DF      FE95     EF
FE16      BD      FE96     DE
FE17      BF      FE97     DF
FE18      7E      FE98     BF    Minor 6th
FE19      DF      FE99     6F
FE1A      FD      FE9A     FE
FE1B      FF      FE9B     FF
FE1C      7B      FE9C     BD    Minor 7th
FE1D      DE      FE9D     EF
FE1E      FF      FE9E     7F
FE1F      FF      FE9F     FF
FE2∅    DB      FEA∅   ED    Minor 9th
FE21      DE      FEA1     EF
FE22      FF      FEA2     7F
FE23      FF      FEA3     FF
FE24      7B      FEA4     BD    7th
FE25      EE      FEA5     F7
FE26      FF      FEA6     7F
FE27      FF      FEA7     FF
FE28      FD      FEA8     FE    Augmented 7th
FE29      ED      FEA9     F6
FE2A      FF      FEAA     FF
FE2B      BF      FEAB     DF
FE2C      DF      FEAC     EF    9th
FE2D      6F      FEAD     B7
FE2E      BF      FEAE     DF
FE2F      FF      FEAF     FF
FE3∅    DD      FEB∅   EE    Augmented 9th
FE31      EE      FEB1     F7
FE32      FF      FEB2     7F
FE33      FF      FEB3     FF
FE34      EE      FEB4     F7    Diminished 7th -FE35 FB FEB5 7D
FE36      BF      FEB6     DF
FE37      FF      FEB7     FF
FE38      FD      FEB8     FE    Augmented
FE39      EF      FEB 9    F7
FE3A      BE      FEBA     DF
FE3B      FF      FEBB     7F
FE3C      FB      FEBC     FD    Suspended 7th
FE3D      F6      FEBD     FB
FE3E      FF      FEBE     7F
FE3F      BF      FEBF     DF
Position 4
FF∅∅  FF      FF8∅   FF    Major
FF∅1    76      FF81     BB
FF∅2    F6      FF82     7B
FF∅3    FF      FF83     7F
FF∅4    DB      FF84     ED    Major 6th
FF∅5    F6      FF85     FB
FF∅6    F7      FF86     7B
FF∅7    FF      FF87     FF
FF∅8    DE      FF88     EF    Major 7th
FF∅9    F6      FF89     7B
FF∅A    F7      FF8A     7B
FF∅B    FF      FF8B     FF
FF∅C    DE      FF8C     EF    Major 9th
FF∅D    F7      FF8D     7B
FF∅E    B7      FF8E     DB
FF∅F    BF      FF8F     DF
FF1∅    DB      FF9∅   ED    Major 6-9
FF11      F6      FF91     FB
FF12      F7      FF92     7B
FF13      BF      FF93     DF
FF14      FF      FF94     FF    Minor
FF15      76      FF95     BB
FF16      F7      FF96     7B
FF17      DF      FF97     EF
FF18      BB      FF98     DD    Minor 6th
FF19      F6      FF99     FB
FF1A      F7      FF9A     7B
FF1B      FF      FF9B     FF
FF1C      FD      FF9C     FE    Minor 7th
FF1D      F6      FF9D     FB
FF1E      FF      FF9E     7F
FF1F      DF      FF9F     EF
FF2∅    7D      FFA∅   BE    Minor 9th
FF21      F7      FFA1     FB
FF22      DF      FFA2     EF
FF23      FF      FFA3     FF
FF24      FD      FFA4     FE    7th
FF25      F6      FFA5     FB
FF26      FF      FFA6     7F
FF27      EF      FFA7     F7
FF28      DD      FFA8     EE    Augmented 7th
FF29      FA      FFA9     FD
FF2A      FF      FFAA     7F
FF2B      FF      FFAB     FF
FF2C      DD      FFAC     EE    9th
FF2D      F6      FFAD     FB
FF2E      F7      FFAE     7B
FF2F      BF      FFAF     DF
FF3∅    DD      FFB∅   EE    Augmented 9th
FF31      FB      FFB1     FD
FF32      BF      FFB2     DF
FF33      FF      FFB3     FF
FF34      FF      FFB4     FF    Diminished 7th
FF35      6F      FFB5     B7
FF36      DD      FFB6     EE
FF37      FF      FFB7     FF
FF38      FF      FFB8     FF    Augmented
FF39      FA      FFB9     FD
FF3A      FB      FFBA     7D
FF3B      7F      FFBB     F7
FF3C      ED      FFBC     F6    Suspended 7th
FF3D      F6      FFBD     FB
FF3E      FF      FFBE     7F
FF3F      FF      FFBF     FF
FF7E       Reset Vector
FFFE    Reset Vector
FF7F       Reset Vector
FFFF    Reset Vector
______________________________________

______________________________________
Schedule `B`
______________________________________
∅∅∅∅
Temporary LED Storage for flashing
∅∅∅1 Key Press Duration group 1
∅∅∅2 Key Press Duration group 2
∅∅∅3 Key Press Duration group 3
∅∅∅4 "S" flag (is chord complete?)
∅∅∅5 Temporary interval Storage register
∅∅∅6 Temporary interval Storage register
∅∅∅7 ROM Address for finger positions on frets
∅∅∅8 ROM Address for finger positions on frets
∅∅∅9 "P" flag (has position been selected?)
∅∅∅A Temporary "KEY" Storage
∅∅∅B ROM Address for fret selection
∅∅∅C ROM Address for fret selection
∅F∅∅ FRET Position Latch
∅F∅1   Latches for finger positions
∅F∅2   Latches for finger positions
∅F∅3   Latches for finger positions
∅F∅4   Latches for finger positions
∅F∅5   T/S buffers for switches
∅F∅6   T/S buffers for switches
∅F∅7   T/S buffers for switches
∅38∅-∅3BF  Valid chord look up table
∅3C∅-∅3FF Fret position ROM table
FC∅∅-FFFD   Finger position ROM table
FFFE-FFFF       Reset Vector
______________________________________

______________________________________
Schedule `B`
Valid Cord Look up Table
______________________________________
∅38∅      A4
∅381        ∅∅
∅382        A5
∅383        1∅
∅384        A5
∅385        ∅∅
∅386        A4
∅387        4∅
∅388        A4
∅389        5∅
∅38A        C4
∅38B        ∅∅
∅38C        C5
∅38D        ∅∅
∅38E        C4
∅38F        4∅
∅39∅      C4
∅391        8∅
∅392        C8
∅393        8∅
∅394        ∅∅
∅395        ∅∅
∅396        C4
∅397        8∅
∅398        C4
∅399        94
∅39A        A4
∅39B        8∅
∅39C        A8
∅39D        8∅
∅39E        A2
∅39F        8∅
∅3A∅      A4
∅3A1        A∅
∅3A2        A4
∅3A3        9∅
∅3A4        A4
∅3A5        88
∅3A6        A8
∅3A7        9∅
∅3A8        A2
∅3A9        9∅
∅3AA        ∅∅
∅3AB        ∅∅
∅3AC        ∅∅
∅3AD        ∅∅
∅3AE        ∅∅
∅3AF        ∅∅
∅3B∅      ∅∅
∅3B1        ∅∅
∅3B2        A4
∅3B3        94
∅3B4        A4
∅3B5        96
∅3B6        C9
∅3B7        ∅∅
∅3B8        94
∅3B9        ∅∅
∅3BA        94
∅3BB        8∅
∅3BC        ∅∅
∅3BD        ∅∅
∅3BE        XX
∅3BF        XX
______________________________________

______________________________________
Schedule `B`
Reset Routine
______________________________________
LDA A     #$∅3
STA A     $∅B
LED Flash INC       $∅∅∅∅
LDA A     $∅∅
STA A     $∅F∅∅
Key Press LDA A     $∅F∅5
TST A
BNE       Key Group 1
LDA A     $∅F∅6
TST A
BNE       Key Group 2
LDA A     $∅F∅7
TST A
BNE       Key Group 3
CLR       $∅∅∅1
CLR       $∅∅∅2
CLR       $∅∅∅3
TST       $∅∅∅4 S Flag
BNE       Key Press
JMP       LED Flash
Key Group 1
CLR       $∅∅∅2
CLR       $∅∅∅3
INC       $∅∅∅1
LDA B     #$32
CMP B     $∅1
BNE       Key Press
TST       $∅∅∅4 S Flag
BNE       "KEY" Key 1
ORA A     $∅5
STA A     $∅5
JMP       LED Flash
Key Group 2
CLR       $∅∅∅1
CLR       $∅∅∅ 3
INC       $∅∅∅2
LDA B     #$32
CMP B     $∅2
BNE       Key Press
TST       $∅∅∅4 S Flag
BNE       "KEY" Key 2
LSR A
BCS       Chord Valid?
ROL A
ORA A     $∅6
STA A     $∅6
JMP       LED Flash
Key Group 3
CLR       $∅∅∅1
CLR       $∅∅∅2
INC       ∅∅∅3
LDA B     #$32
CMP B     $∅3
BNE       Key Press
LDA B     #$FC
STA B     $∅∅∅7
LDA B     #$∅3
Pos Search
LSR A
BCS       Display
INC       $∅∅∅7
DEC B
BEQ       Display
JMP       Pos Search
Chord Valid
CLR A
LDX       #$∅38∅
Test      CPX       $∅5
BEQ       Valid
INX
INX
ADD A     #$∅4
CMP A     #$7C
BEQ       Reset       (Invalid Chord)
JMP       Test
Valid     STA A     $∅8
LDA A     #$∅1
STA A     $∅4       Set `S` Flag
JMP       Key Press
"KEY" Key 1
CLR       $∅∅∅A
LDA B     #$∅7
Key Search 1
ROL A
BCS       Display + 1
INC       $∅∅∅A
DEC B
BEQ       Key Press
JMP       Key Search 1
"KEY" Key 2
LDA B     #$∅8
STA B     $∅A
LDA B     #∅3
Key Search 2
ROL A
BCS       Display + 1
INC       $∅∅∅A
DEC B
BEQ       Key Press
JMP       Key Search 2
Display   LDA A     #$∅1
STA A     $∅9       Set `P` Flag
Display + 1
TST       $∅∅∅9
BEQ       Key Press
TST       $∅∅∅4
BEQ       Key Press
LDA A     #$∅F
AND A     $∅7
ASL A
ASL A
ASL A
ASL A
ORA A     $∅A
STA A     $∅C
LDX       $∅B
LDA A, X  ∅∅
STA A     $∅F∅∅
LDX       $∅7
LDA A, X  ∅∅
STA A     $∅F∅1
LDA A, X  ∅1
STA A     $∅F∅2
LDA A, X  ∅2
STA A     $∅F∅3
LDA A, X  ∅3
STA A     $∅F∅4
JMP       Key Press
______________________________________

______________________________________
Schedule `B`
Fret Position ROM Table
______________________________________
Position 1
∅3C∅   ∅∅    C
∅3C1     ∅1      C♯
∅3C2     ∅2      D
∅3C3     ∅3      D♯
∅3C4     ∅4      E
∅3C5     ∅5      F
∅3C6     ∅6      F♯
∅3C7     ∅7      G
∅3C8     ∅8      G♯
∅3C9     ∅9      A
∅3CA     ∅A      A♯
∅3CB     ∅B      B
Position 2
∅3D∅   ∅3      C
∅3D1     ∅4      C♯
∅3D2     ∅5      D
∅3D3     ∅6      D♯
∅3D4     ∅7      E
∅3D5     ∅8      F
∅3D6     ∅9      F♯
∅3D7     ∅A      G
∅3D8     ∅B      G♯
∅3D9     ∅∅    A
∅3DA     ∅1      A♯
∅3DB     ∅2      B
Position 3
∅3E∅   ∅8      C
∅3E1     ∅9      C♯
∅3E2     ∅A      D
∅3E3     ∅B      D♯
∅3E4     ∅∅    E
∅3E5     ∅1      F
∅3E6     ∅2      F♯
∅3E7     ∅3      G
∅3E8     ∅4      G♯
∅3E9     ∅5      A
∅3EA     ∅6      A♯
∅3EB     ∅7      B
Position 4
∅3F∅   ∅A      C
∅3F1     ∅B      C♯
∅3F2     ∅∅    D
∅3F3     ∅1      D♯
∅3F4     ∅2      E
∅3F5     ∅3      F
∅3F6     ∅4      F♯
∅3F7     ∅5      G
∅3F8     ∅6      G♯
∅3F9     ∅7      A
∅3FA     ∅8      A♯
∅3FB     ∅9      B
______________________________________

SCHEDULE `B`
______________________________________
Finger Position ROM Table
______________________________________
Position 1
FC∅∅
7D         FC8∅  BE       Major
FC∅1
DF         FC81    EF
FC∅2
BE         FC82    DF
FC∅3
EF         FC83    77
FC∅4
7F         FC84    BF       Major 6-9
FC∅5
77         FC85    BB
FC∅6
BF         FC86    DF
FC∅7
F7         FC87    FB
FC∅8
ED         FC88    F6       Major 6th
FC∅9
F7         FC89    FB
FC∅A
BF         FC8A    DF
FC∅B
FF         FC8B    FF
FC∅C
7B         FC8C    BD       Major 7th
FC∅D
DF         FC8D    EF
FC∅E
BE         FC8E    DF
FC∅F
F7         FC8F    7B
FC1∅
7B         FC9∅  BD       Major 9th
FC11  DE         FC91    EF
FC12  FE         FC92    7F
FC13  FF         FC93    7F
FC14  B5         FC94    B5       Minor
FC15  A5         FC95    A5
FC16  4B         FC96    4B
FC17  5B         FC97    5B
FC18  EF         FC98    F7       Minor 6th
FC19  F6         FC99    FB
FC1A  F7         FC9A    7B
FC1B  F7         FC9B    FB
FC1C  FB         FC9C    FD       Minor +7
FC1D  DF         FC9D    EF
FC1E  7E         FC9E    BF
FC1F  FF         FC9F    7F
FC2∅
ED         FCA∅  F6       Minor 7th
FC21  FB         FCA1    FD
FC22  BF         FCA2    DF
FC23  FF         FCA3    FF
FC24  DD         FCA4    EE       Minor 7th (b5)
FC25  FB         FCA5    FD
FC26  7F         FCA6    BF
FC27  FF         FCA7    FF
FC28  XX         FCA8    XX       N/A
FC29  XX         FCA9    XX
FC2A  XX         FCAA    XX
FC2B  XX         FCAB    XX
FC2C  EF         FCAC    F7       Minor 9th
FC2D  7B         FCAD    BD
FC2E  7F         FCAE    BF
FC2F  FF         FCAF    FF
FC3∅
BF         FCB∅  DF       Minor 11th
FC31  7B         FCB1    BD
FC32  7F         FCB2    BF
FC33  FF         FCB3    FF
FC34  7D         FCB4    BE       7th
FC35  FB         FCB5    FD
FC36  BE         FCB6    DF
FC37  F7         FCB7    7B
FC38  DD         FCB8    EE       7th (b5)
FC39  FB         FCB9    FD
FC3A  BF         FCBA    DF
FC3B  FF         FCBB    FF
FC3C  FD         FCBC    FE       7th (#5)
FC3D  EF         FCBD    F7
FC3E  BB         FCBE    DD
FC3F  BF         FCBF    DF
FC4∅
EE         FCC∅  F7       7th (b9)
FC41  FB         FCC1    7D
FC42  BF         FCC2    DF
FC43  FF         FCC3    FF
FC44  EF         FCC4    F7       9th
FC45  7B         FCC5    BD
FC46  BF         FCC6    DF
FC47  BF         FCC7    DF
FC48  FD         FCC8    FE       7th (#9)
FC49  DF         FCC9    EF
FC4A  7B         FCCA    BD
FC4B  BF         FCCB    DF
FC4C  DF         FCCC    EF       9th (b5)
FC4D  7B         FCCD    BD
FC4E  BE         FCCE    DF
FC4F  FF         FCCF    7F
FC5∅
7D         FCD∅  BE       9th (#5)
FC51  EE         FCD1    F7
FC52  FB         FCD2    7D
FC53  BF         FCD3    DF
FC54  XX         FCD4    XX       N/A
FC55  XX         FCD5    XX
FC56  XX         FCD6    XX
FC57  XX         FCD7    XX
FC58  XX         FCD8    XX       N/A
FC59  XX         FCD9    XX
FC5A  XX         FCDA    XX
FC5B  XX         FCDB    XX
FC5C  XX         FCDC    XX       N/A
FC5D  XX         FCDD    XX
FC5E  XX         FCDE    XX
FC5F  XX         FCDF    XX
FC6∅
XX         FCE∅  XX       N/A
FC61  XX         FCE1    XX
FC62  XX         FCE2    XX
FC63  XX         FCE3    XX
FC64  B5         FCE4    B5       11th
FC65  A5         FCE5    A5
FC66  4B         FCE6    4B
FC67  5B         FCE7    5B
FC68  B5         FCE8    B5       13th
FC69  A5         FCE9    A5
FC6A  4B         FCEA    4B
FC6B  5B         FCEB    5B
FC6C  DD         FCEC    EE       Diminished 7th
FC6D  F7         FCED    FB
FC6E  7F         FCEE    BF
FC6F  FF         FCEF    FF
FC7∅
FD         FCF∅  FE       Suspended
FC71  DF         FCF1    EF
FC72  DE         FCF2    EF
FC73  FF         FCF3    7F
FC74  ED         FCF4    F6       Suspended 7th
FC75  FB         FCF5    FD
FC76  DF         FCF6    EF
FC77  FF         FCF7    FF
FC78  XX         FCF8    XX       N/A
FC79  XX         FCF9    XX
FC7A  XX         FCFA    XX
FC7B  XX         FCFB    XX
FC7C  XX         FCFC    XX       N/A
FC7D  XX         FCFD    XX
FC7E  XX         FCFE    XX
FC7F  XX         FCFF    XX
Position 2
FD∅∅
7E         FD8∅  BF       Major
FD∅1
F7         FD81    7B
FD∅2
BF         FD82    DF
FD∅3
FF         FD83    FF
FD∅4
B5         FD84    B5       Major 6-9
FD∅5
A5         FD85    A5
FD∅6
4B         FD86    4B
FD∅7
5B         FD87    5B
FD∅8
DE         FD88    EF       Major 6th
FD∅9
F7         FD89    7B
FD∅A
BF         FD8A    DF
FD∅B
FF         FD8B    FF
FD∅C
7E         FD8C    BF       Major 7th
FD∅D
EF         FD8D    77
FD∅E
F7         FD8E    FB
FD∅F
FF         FD8F    FF
FD1∅
7E         FD9∅  BF       Major 9th
FD11  EF         FD91    77
FD12  FD         FD92    FE
FD13  BF         FD93    DF
FD14  7D         FD94    BE       Minor
FD15  F7         FD95    FB
FD16  BF         FD96    DF
FD17  FF         FD97    FF
FD18  DD         FD98    EE       Minor 6th
FD19  F7         FD99    FB
FD1A  BF         FD9A    DF
FD1B  FF         FD9B    FF
FD1C  7D         FD9C    BF       Minor +7
FD1D  EF         FD9D    F7
FD1E  B7         FD9E    DB
FD1F  BF         FD9F    DF
FD2∅
ED         FDA∅  F6       Minor 7th
FD21  DF         FDA1    EF
FD22  B7         FDA2    DB
FD23  BF         FDA3    DF
FD24  FD         FDA4    FE       Minor 7th (b5)
FD25  DF         FDA5    EF
FD26  77         FDA6    BB
FD27  FF         FDA7    FF
FD28  XX         FDA8    XX       N/A
FD29  XX         FDA9    XX
FD2A  XX         FDAA    XX
FD2B  XX         FDAB    XX
FD2C  FB         FDAC    FD       Minor 9th
FD2D  DF         FDAD    EF
FD2E  BE         FDAE    DF
FD2F  FF         FDAF    7F
FD3∅
FB         FDB∅  FD       Minor 11th
FD31  DE         FDB1    EF
FD32  FE         FDB2    7F
FD33  FF         FDB3    7F
FD34  FE         FDB4    FF       7th
FD35  DF         FDB5    6F
FD36  B7         FDB6    DB
FD37  FF         FDB7    FF
FD38  EE         FDB8    F7       7th (b5)
FD39  F7         FDB9    7B
FD3A  7F         FDBA    BF
FD3B  FF         FDBB    FF
FD3C  BE         FDBC    DF       7th (#5)
FD3D  DF         FDBD    6F
FD3E  D7         FDBE    EB
FD3F  FF         FDBF    FF
FD4∅
7E         FDC∅  BF       7th (b9)
FD41  DF         FDC1    6F
FD42  BB         FDC2    DD
FD43  BF         FDC3    DF
FD44  FB         FDC4    FD       9th
FD45  DF         FDC5    EF
FD46  B7         FDC6    DB
FD47  BF         FDC7    DF
FD48  FD         FDC8    FE       7th (#9)
FD49  DF         FDC9    EF
FD4A  B7         FDCA    DB
FD4B  FF         FDCB    FF
FD4C  B5         FDCC    B5       9th (b5)
FD4D  A5         FDCD    A5
FD4E  4B         FDCE    4B
FD4F  5B         FDCF    5B
FD5∅
EE         FDD∅  FF       9th (#5)
FD51  F7         FDD1    BB
FD52  DD         FDD2    DF
FD53  FF         FDD3    FB
FD54  XX         FDD4    XX       N/A
FD55  XX         FDD5    XX
FD56  XX         FDD6    XX
FD57  XX         FDD7    XX
FD58  XX         FDD8    XX       N/A
FD59  XX         FDD9    XX
FD5A  XX         FDDA    XX
FD5B  XX         FDDB    XX
FD5C  XX         FDDC    XX       N/A
FD5D  XX         FDDD    XX
FD5E  XX         FDDE    XX
FD5F  XX         FDDF    XX
FD6∅
XX         FDE∅  XX       N/A
FD61  XX         FDE1    XX
FD62  XX         FDE2    XX
FD63  XX         FDE3    XX
FD64  7B         FDE4    BD       11th
FD65  DE         FDE5    EF
FD66  FF         FDE6    7F
FD67  FF         FDE7    FF
FD68  EE         FDE8    F7       13th
FD69  F7         FDE9    7B
FD6A  BD         FDEA    DE
FD6B  EF         FDEB    F7
FD6C  FD         FDEC    FE       Diminished 7th
FD6D  F7         FDED    FB
FD6E  7F         FDEE    BF
FD6F  EF         FDEF    F7
FD7∅
7F         FDF∅  BF       Suspended
FD71  76         FDF1    BB
FD72  F7         FDF2    7B
FD73  BF         FDF3    DF
FD74  FF         FDF4    FF       Suspended 7th
FD75  77         FDF5    BB
FD76  FF         FDF6    DF
FD77  F7         FDF7    FB
FD78  XX         FDF8    XX       N/A
FD79  XX         FDF9    XX
FD7A  XX         FDFA    XX
FD7B  XX         FDFB    XX
FD7C  XX         FDFC    XX       N/A
FD7D  XX         FDFD    XX
FD7E  XX         FDFE    XX
FD7F  XX         FDFF    XX
Position 3
FE∅∅
7B         FE8∅  BD       Major
FE∅1
EF         FE81    F7
FE∅2
BD         FE82    DE
FE∅3
FF         FE83    FF
FE∅4
DE         FE84    EF       Major 6-9
FE∅5
EF         FE85    77
FE∅6
FD         FE86    FE
FE∅7
BF         FE87    DF
FE∅8
7E         FE88    BF       Major 6th
FE∅9
EF         FE89    77
FE∅A
BD         FE8A    DE
FE∅B
BF         FE8B    DF
FE∅C
7B         FE8C    BD       Major 7th
FE∅D
EF         FE8D    F7
FE∅E
7F         FE8E    BF
FE∅F
FF         FE8F    FF
FE1∅
DB         FE9∅  ED       Major 9th
FE11  EF         FE91    F7
FE12  7F         FE92    BF
FE13  FF         FE93    FF
FE14  7B         FE94    BD       Minor
FE15  DF         FE95    EF
FE16  BD         FE96    DE
FE17  BF         FE97    DF
FE18  7E         FE98    BF       Minor 6th
FE19  DF         FE99    6F
FE1A  FD         FE9A    FE
FE1B  FF         FE9B    FF
FE1C  7B         FE9C    BD       Minor +7
FE1D  DF         FE9D    EF
FE1E  7D         FE9E    BE
FE1F  BF         FE9F    DF
FE2∅
7B         FEA∅  BD       Minor 7th
FE21  DE         FEA1    EF
FE22  FF         FEA2    7F
FE23  FF         FEA3    FF
FE24  EF         FEA4    F7       Minor 7th (b5)
FE25  7B         FEA5    BD
FE26  BF         FEA6    DF
FE27  FF         FEA7    FF
FE28  XX         FEA8    XX       N/A
FE29  XX         FEA9    XX
FE2A  XX         FEAA    XX
FE2B  XX         FEAB    XX
FE2C  DB         FEAC    ED       Minor 9th
FE2D  DE         FEAD    EF
FE2E  FF         FEAE    7F
FE2F  FF         FEAF    FF
FE3∅
DB         FEB∅  ED       Minor 11th
FE31  DE         FEB1    EF
FE32  F7         FEB2    7B
FE33  FF         FEB3    FF
FE34  7B         FEB4    BD       7th
FE35  EE         FEB5    F7
FE36  FF         FEB6    7F
FE37  FF         FEB7    FF
FE38  FF         FEB8    FF       7th (b5)
FE39  EE         FEB9    F7
FE3A  FB         FEBA    7D
FE3B  BF         FEBB    DF
FE3C  FD         FEBC    FE       7th (#5)
FE3D  ED         FEBD    F6
FE3E  FF         FEBE    FF
FE3F  BF         FEBF    DF
FE4∅
FF         FEC∅  FF       7th (b9)
FE41  EE         FEC1    F7
FE42  FD         FEC2    7E
FE43  DF         FEC3    EF
FE44  DF         FEC4    EF       9th
FE45  6F         FEC5    B7
FE46  BF         FEC6    DF
FE47  FF         FEC7    FF
FE48  EB         FEC8    F5       7th (#9)
FE49  EE         FEC9    F7
FE4A  FD         FECA    7E
FE4B  BF         FECB    DF
FE4C  FF         FECC    FF       9th (b5)
FE4D  EE         FECD    F7
FE4E  FB         FECE    7D
FE4F  EF         FECF    F7
FE5∅
DD         FED∅  EE       9th (#5)
FE51  EE         FED1    F7
FE52  FF         FED2    7F
FE53  FF         FED3    FF
FE54  XX         FED4    XX       N/A
FE55  XX         FED5    XX
FE56  XX         FED6    XX
FE57  XX         FED7    XX
FE58  XX         FED8    XX       N/A
FE59  XX         FED9    XX
FE5A  XX         FEDA    XX
FE5B  XX         FEDB    XX
FE5C  XX         FEDC    XX       N/A
FE5D  XX         FEDD    XX
FE5E  XX         FEDE    XX
FE5F  XX         FEDF    XX
FE6∅
XX         FEE∅  XX       N/A
FE61  XX         FEE1    XX
FE62  XX         FEE2    XX
FE63  XX         FEE3    XX
FE64  DB         FEE4    ED       11th
FE65  F6         FEE5    FB
FE66  FF         FEE6    7F
FE67  FF         FEE7    FF
FE68  DE         FEE8    EF       13th
FE69  EE         FEE9    77
FE6A  FD         FEEA    7E
FE6B  BF         FEEB    DF
FE6C  EE         FEEC    F7       Diminished 7th
FE6D  FB         FEED    7D
FE6E  BF         FEEE    DF
FE6F  FF         FEEF    FF
FE7∅
7B         FEF∅  BD       Suspended
FE71  F7         FEF1    FB
FE72  B7         FEF2    DB
FE73  FF         FEF3    FF
FE74  FB         FEF4    FD       Suspended 7th
FE75  F6         FEF5    FB
FE76  FF         FEF6    7F
FE77  BF         FEF7    DF
FE78  XX         FEF8    XX       N/A
FE79  XX         FEF9    XX
FE7A  XX         FEFA    XX
FE7B  XX         FEFB    XX
FE7C  XX         FEFC    XX       N/A
FE7D  XX         FEFD    XX
FE7E  XX         FEFE    XX
FE7F  XX         FEFF    XX
Position 4
FF∅∅
FF         FF8∅  FF       Major
FF∅1
76         FF81    BB
FF∅2
F6         FF82    7B
FF∅3
FF         FF83    7F
FF∅4
DB         FF84    ED       Major 6-9
FF∅5
F6         FF85    FB
FF∅6
F7         FF86    7B
FF∅7
BF         FF87    DF
FF∅8
DB         FF88    ED       Major 6th
FF∅9
F6         FF89    FB
FF∅A
F7         FF8A    7B
FF∅B
FF         FF8B    FF
FF∅C
DE         FF8C    EF       Major 7th
FF∅D
F6         FF8D    7B
FF∅E
F7         FF8E    7B
FF∅F
FF         FF8F    FF
FF1∅
DE         FF9∅  EF       Major 9th
FF11  F7         FF91    7B
FF12  B7         FF92    DB
FF13  BF         FF93    DF
FF14  FF         FF94    FF       Minor
FF15  76         FF95    BB
FF16  F7         FF96    7B
FF17  DF         FF97    EF
FF18  BB         FF98    DD       Minor 6th
FF19  F6         FF99    FB
FF1A  F7         FF9A    7B
FF1B  FF         FF9B    FF
FF1C  BE         FF9C    DF       Minor +7
FF1D  F6         FF9D    7B
FF1E  F7         FF9E    7B
FF1F  FF         FF9F    FF
FF2∅
FD         FFA∅  FE       Minor 7th
FF21  F6         FFA1    FB
FF22  FF         FFA2    7F
FF23  DF         FFA3    EF
FF24  FD         FFA4    FE       Minor 7th (b5)
FF25  EE         FFA5    F7
FF26  FB         FFA6    7D
FF27  FF         FFA7    FF
FF28  XX         FFA8    XX       N/A
FF29  XX         FFA9    XX
FF2A  XX         FFAA    XX
FF2B  XX         FFAB    XX
FF2C  7D         FFAC    BE       Minor 9th
FF2D  F7         FFAD    FB
FF2E  DF         FFAE    EF
FF2F  FF         FFAF    FF
FF3∅
7D         FFB∅  BE       Minor 11th
FF31  DE         FFB1    EF
FF32  F7         FFB2    7B
FF33  FF         FFB3    FF
FF34  FD         FFB4    FE       7th
FF35  F6         FFB5    FB
FF36  FF         FFB6    7F
FF37  EF         FFB7    F7
FF38  DD         FFB8    EE       7th (b5)
FF39  EE         FFB9    F7
FF3A  FF         FFBA    7F
FF3B  FF         FFBB    FF
FF3C  DD         FFBC    EE       7th (#5)
FF3D  FA         FFBD    FD
FF3E  FF         FFBE    7F
FF3F  FF         FFBF    FF
FF4∅
DD         FFC∅  EE       7th (b9)
FF41  F7         FFC1    FB
FF42  7F         FFC2    BF
FF43  FF         FFC3    FF
FF44  DD         FFC4    EE       9th
FF45  F6         FFC5    FB
FF46  F7         FFC6    7B
FF47  BF         FFC7    DF
FF48  BD         FFC8    DE       7th (#9)
FF49  F6         FFC9    FB
FF4A  F7         FFCA    7B
FF4B  FF         FFCB    FF
FF4C  FD         FFCC    FE       9th (b5)
FF4D  EF         FFCD    F7
FF4E  BF         FFCE    DF
FF4F  EF         FFCF    F7
FF5∅
DD         FFD∅  EE       9th (#5)
FF51  FB         FFD1    FD
FF52  BF         FFD2    DF
FF53  FF         FFD3    FF
FF54  XX         FFD4    XX       N/A
FF55  XX         FFD5    XX
FF56  XX         FFD6    XX
FF57  XX         FFD7    XX
FF58  XX         FFD8    XX       N/A
FF59  XX         FFD9    XX
FF5A  XX         FFDA    XX
FF5B  XX         FFDB    XX
FF5C  XX         FFDC    XX       N/A
FF5D  XX         FFDD    XX
FF5E  XX         FFDE    XX
FF5F  XX         FFDF    XX
FF6∅
XX         FFE∅  XX       N/A
FF61  XX         FFE1    XX
FF62  XX         FFE2    XX
FF63  XX         FFE3    XX
FF64  7D         FFE4    BE       11th
FF65  DF         FFE5    EF
FF66  F7         FFE6    FB
FF67  FF         FFE7    FF
FF68  B5         FFE8    B5       13th
FF69  A5         FFE9    A5
FF6A  4B         FFEA    4B
FF6B  5B         FFEB    5B
FF6C  FF         FFEC    EF       Diminished 7th
FF6D  6F         FFED    B7
FF6E  DD         FFEE    EE
FF6F  FF         FFEF    FF
FF7∅
EF         FFF∅  F7       Suspended
FF71  76         FFF1    BB
FF72  F7         FFF2    7B
FF73  FF         FFF3    FF
FF74  ED         FFF4    F6       Suspended 7th
FF75  F6         FFF5    FB
FF76  FF         FFF6    7F
FF77  FF         FFF7    FF
FF78  XX         FFF8    XX       N/A
FF79  XX         FFF9    XX
FF7A  XX         FFFA    XX
FF7B  XX         FFFB    XX
FF7C  XX         FFFC    XX       N/A
FF7D  XX         FFFD    XX
FF7E  Reset Vector
FFFE    Reset Vector
FF7F  Reset Vector
FFFF    Reset Vector
______________________________________

Claims

1. An electronic device in the nature of a hand held calculator, for illustrating on a display area the required string and fret positions of a fretted stringed instrument to be fingered to play the notes making up a particular chord, comprising:

(a) a series of manually operable basic chord information buttons, each associated with a corresponding chord information switch, one chord information switch for each chord for which finger position information is desired;

(b) a visual representation of the strings of the fretted instrument and of the frets over a particular range;

(c) electronically actuated fret and string finger position indicator means associated with the fret and string representation, each of the string finger positions for each of the frets having electronically actuable indicator means associated with it;

(d) electronically actuated open string position indicator means associated with each string of the fret and string representation to indicate when a corresponding string is not fingered;

(e) electronically actuated first fret reference indicator means to represent a fret reference point for a selected chord;

(f) manually operable select means associated with select switch means;

(g) ROM means programmed with chord table information relating chords to desired keys with related fret and string finger position information;

(h) microprocessor means electronically associated with the chord information switches, open string position indicator means, first fret reference indicator means, fret and string finger position indicator means and select switch means, the microprocessor adapted to store information concerning the particular chord information switch or switches actuated until the select switch means is actuated, and then search the ROM for fret and finger position information corresponding to the chord information switch or switches actuated, and display that information on the appropriate fret and string finger position indicator means, open string position means and first fret reference indicator means;

(i) manually operable switch means electronically associated with the microprocessor and fret and string finger position indicator means to clear information displayed on the fret and string representation as required; whereby the device provides an accurate visible indication on the fret and string representation, of the strings and fret positions to be fingered for a selected predetermined chord.

2. A device according to claim 1 wherein the fret and string representation of the strings is of a four fret range.

3. A device according to claim 1 wherein each key in the chromatic scale is represented by a basic chord information button and corresponding chord information switch, each such switch being not simultaneously actuable with respect to other such chord switches and wherein a series of chord indicator buttons and corresponding chord indicator switches representing types of chords are further provided, the chord indicator switches being electronically associated with the microprocessor and each being not simultaneously actuable with each other but simultaneously actuable with the chord information switches, the microprocessor being also adapted to store information regarding the particular chord indicator switch actuated until the select switch means is actuated, and then to search the ROM means for fret and finger position information corresponding to the chord information and the chord indicator switches which are actuated and display that information on the appropriate fret and string finger position indictor means, open string position indicator means and first fret reference indicator means.

4. A device according to claim 3 wherein each chord indicator button and corresponding chord indicator switch corresponds to a chord type selected from the following group: major, minor, diminished, augmented, suspended.

5. A device according to claim 4 wherein each chord indicator button and corresponding chord indicator switch corresponds to a different chord type selected from the group consisting of major, minor, diminished, dominant, augmented, suspended, 6, 7 and 9.

6. A device according to claim 1 further provided with LED on/off indicator means electronically associated with the device to indicate when the device is on.

7. A device according to claim 1 wherein a series of chord alternative position indicator buttons and corresponding chord alternative position indicator switches are further provided, the chord alternative position indicator switches being electronically associated with the microprocessor and being each simultaneously actuable with the chord information switches but independently and not simultaneously actuable with other chord alternative position indicator switches; the ROM means being programmed with chord table information relating to alternative chord positions for chords and desired keys with related alternative fret and string finger position, the microprocessor being also adapted to store information concerning the particular chord alternative position indicator switch actuated until the select switch is actuated, and then search the ROM for fret and string finger position information corresponding to the particular chord information switch and chord alternative position indicator switch actuated and display that information on the appropriate string and fret position indicator means, open string position indicator means and first fret reference indicator means.

8. A device according to claim 1 further provided with a tape recorder and playback means electronically associated therewith to record characteristic signals received from the microprocessor relating to a sequence of selected chords and to enable playback of those signals to the microprocessor to cause to be illustrated on the fret and finger position representation an identical sequence of chord finger positions.